This is the new version of the steal time series, this time on steroids.The steal time per se is not much different from the last time I posted, soI'll highlight what's around it.

Since one of the main fights was around how to register the shared memory area,which would end up with a new MSR, I decided to provide an MSR to end all MSRallocations. This patchset contains a generic GuestKernel-to-Hypervisor memoryregistering, that can be further used and abused without too much hassle, even byletting userspace handle what the hypervisor won't - think of feature emulation inolder hosts, or any other thing.

To demonstrate that, and how it works, I ported kvmclock to this infrastructure.After that, I used it to implement steal time information exchange.

Even our last discussions, I am keeping the steal time accounting in sched.c.I still see value on that, as opposed to a lower level, because it will give useasier access to the scheduler variables, such as the cpu runqueue.

The last patch in the series uses this to decrease CPU power according to thecurrent steal time information, leading to a possibly more smart scheduling.This, in particular, is very early work, and advise on that - including "Stop now,you idiot!" is very welcome.

TODO: * Handle unregister over reboots * Grab a list of current registrations, for migration * Write documentation * Check size in hv registerings, to prevent out of boundaries exploits